This invention relates to halohydrocarbon polymer compositions which contain combustible plasticizers or plasticizing modifier.
The use of halohydrocarbon polymers in the fabrication of rigid moldings, housings, and insulation for electrical appliances and so forth is widespread. Such halohydrocarbon polymers such as polyvinyl chloride are normally self-extinguishing. However, it is often desirable, in order to achieve the desired molding characteristics of the polymer and flexibility of the resultant article, to incorporate therein a significant amount of plasticizer. Characteristically, these plasticizers are combustible and therefore significantly impair the inherent self-extinguishing characteristics of the halohydrocarbon polymer. In fact, the amount of plasticizer normally required to produce the desired molding characteristics and article flexibility generally renders the resultant halohydrocarbon polymer composition flammable or causes such a significant loss of fire retardance that the composition does not pass standard flame retardance tests required in the manufacture of plastic articles.
In recent times, it has become increasingly important to impart flame resistance properties to these plasticized halohydrocarbon polymers. This is particularly true where the plasticized halohydrocarbon polymers are used as insulating materials in the electrical industry and to prevent the risk of fire in the daily use of other items.
It has been proposed heretofore to impart flame retardancy to such flammable halohydrocarbon polymers by incorporating various additives into the polymer. Flame retardance has been obtained, for instance, by combining the polymer containing the plasticizer with a flame retardant inorganic oxide, preferably antimony oxide.
In view of the relatively high cost, the possible ecological hazards of antimony oxide, and the substantial amount by weight which must be employed to achieve the desired degree of fire retardancy in such flammable halohydrocarbon polymer compositions, it would be highly desirable to provide a more economical and non-toxic means for rendering normally flammable halohydrocarbon polymer compositions flame retardant or self-extinguishing.